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排序方式: 共有866条查询结果,搜索用时 15 毫秒
81.
82.
WM Feinberg ES Cornell SD Nightingale LA Pearce RP Tracy RG Hart EG Bovill 《Canadian Metallurgical Quarterly》1997,28(6):1101-1106
BACKGROUND AND PURPOSE: The prothrombin time (expressed as the international normalized ratio [INR]) is the standard method of monitoring warfarin therapy in patients with atrial fibrillation. Prothrombin activation fragment F1.2 provides an index of in vivo thrombin generation and might provide a better index of the effective intensity of anticoagulation. We examined the relationship between F1.2 and INR in patients with atrial fibrillation. METHODS: We measured INR and F1.2 levels in 846 patients with atrial fibrillation participating in the Stroke Prevention in Atrial Fibrillation III study. Two hundred nineteen (26%) were taking aspirin alone, 326 (39%) were taking adjusted-dose warfarin, and 301 (36%) were taking a low fixed dose of warfarin (1 to 3 mg) plus aspirin (combination therapy). F1.2 levels were measured with an enzyme-linked immunosorbent assay. RESULTS: Patients receiving adjusted-dose warfarin or combination therapy had significantly higher INR and significantly lower F1.2 values than those on aspirin alone (P < or = .0001 for each of the four comparisons). F1.2 values (nanomolar) were inversely correlated with INR (F1.2 = -0.1 + 2.3[1/INR]; R2 = .37; P < .0001; simple linear regression). However, significant variability remained. Among patients receiving warfarin, older patients had higher F1.2 values than younger patients after adjustment for INR intensity (P < .001) in the model. There was no difference in the relationship between F1.2 and INR between men and women. CONCLUSIONS: Increasing intensity of anticoagulation, as measured by the INR, is associated with decreasing thrombin generation as measured by the F1.2 level, but significant variability exists in this relationship. Older anticoagulated patients have higher F1.2 values than younger patients at equivalent INR values. The clinical significance of these differences is not clear. F1.2 measurement might provide information regarding anticoagulation intensity in addition to that reflected by the INR. 相似文献
83.
D Robinson KF Pearce JS Preisser E Dugan PK Suggs SJ Cohen 《Canadian Metallurgical Quarterly》1998,91(2):224-228
The aim of the present study was to assess the effect of normal growth and development on the Peer Assessment Rating index between 12 and 22 years of age. The sample consisted of 49 nonorthodontic subjects (24 male and 25 females) from the Nijmegen Growth Study. The mean age at the first observation was 12.2 +/- 0.7 years and at the second observation 22.1 +/- 0.6 years. The dental casts at these ages were scored with the Peer Assessment Rating index. The influence of the Angle classification and the treatment need on changes over time in the Peer Assessment Rating score were evaluated. The mean changes in the PAR scores over time between cases that have more than 30% improvement to those that have less than 30% improvement were calculated. The results indicate that there were no significant differences between the mean Peer Assessment Rating score at 12 years of age (12.20 +/- 0.91) and at 22 years of age (12.45 +/- 1.28), but there were relevant differences in individual cases. The changes were irrespective of the Angle classification or the treatment need. Changes over time in the weighted Peer Assessment Rating score were mainly correlated to changes in the anterior crossbite and the overjet. This correlation may be influenced, however, by the applied weighting factor for those occlusal traits. 相似文献
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设计师们正在对一些新的设计方法进行评估,以期加快设计周期,缓解因新产品上市时间日趋加快带来的前所未有的重压。其中所建议使用的加速SoC设计周期的方法之一是硬件/软件的协同设计。拥有一种功能强大的协同设计工具可使设计理念大幅提升到系统级,从而改善硬件和软件设计小组之间的信息交流。同时它的使用还能有效地保护在RTL设计实现流程方面的现有投资。一些厂家已宣布,采用硬件/软件协同设计技术已使其设计时间减少一半,生产效率大为提高。那么,什么是真正的硬件/软件协同设计,它对设计小组又有怎样的意义?为此,本文将对硬… 相似文献
88.
Pete Lipetzky Steven R. Nutt David A. Koester Robert F. Davis 《Journal of the American Ceramic Society》1991,74(6):1240-1247
A SiC-whisker-reinforced alumina composite was crept in compression at 1200° to 1400°C in an air ambient and in nitrogen. The data were described by a power-law-type constitutive relation. The measured value of the stress exponent was n = 1 at 1200°C and n = 3 at 1300° and 1400°C in both ambients. TEM observations were correlated with the measured creep response to determine active deformation mechanisms. Values of n = 1 were associated with diffusional creep and unaccommodated grain-boundary sliding, while values of n = 3 were associated with increased microstructural damage in the form of cavities. Experiments conducted in circulated air resulted in higher creep rates than comparable experiments in nitrogen. The accelerated creep rates were caused by the thermal oxidation of SiC and the resultant formation of a vitreous phase along composite interfaces. The glassy phase facilitated cavitation, weakened interfaces, and enhanced boundary diffusion. 相似文献
89.
90.
Folahan O. Ayorinde Erick Y. Nana Pete D. Nicely Anthony S. Woods Elvis O. Price Chukwuma P. Nwaonicha 《Journal of the American Oil Chemists' Society》1997,74(5):531-538
12-Aminododecanoic acid and 11-aminoundecanoic acid, monomer precursors for nylon-12 and nylon-11, respectively, have been
synthesized from vernolic (cis-12,13-epoxy-cis-9-octadecenoic) acid via a reaction sequence that includes the formation of 12-oxododecanoic acid oxime. Saponification of vernonia oil, followed
by a low-temperature recrystallization at −20°C, gave 51% vernolic acid (97% purity, m.p. 23–25°C). Hydrogenation afforded
cis-12,13-epoxystearic acid (m.p. 52–54°C, lit. m.p. 52–54°C), which upon oxidation with periodic acid in tertiary butyl alcohol
gave 12-oxododecanoic acid with an isolated yield of 71.0%. Reaction of the oxoacid with hydroxylamine hydrochloride gave
12-oxododecanoic acid oxime, which was catalytically reduced to give 12-aminododecanoic acid with a yield greater than 85%
and a melting point of 184–186°C (lit. m.p. 185–187°C). 11-Aminoundecanoic acid was prepared from the 12-oxododecanoic acid
oxime via a three-step reaction sequence that involved a Beckmann rearrangement, Hofmann degradation, and hydrolysis. Thus, the aldoxime
acid was hydrolyzed in the presence of nickel acetate tetrahydrate to give 11-carbamoylundecanoic acid (48% yield, m.p. 129–131°C,
lit. m.p. 129–130°C). The amide was then treated with a solution of sodium methoxide and bromine at 70–80°C to give 11-(methoxycarbonylamino)undecanoic
acid at 75% yield (m.p. 84–86°C; elemental analysis, calculated for C13H25NO4: C, 60.19; H, 9.73; N, 5.40; O, 24.68%; found C, 60.02; H, 9.81; N, 5.26; O, 24.91%), which upon alkaline hydrolysis and
subsequent neutralization gave 11-aminoundecanoic acid at 34% yield (m.p. 189–192°C, lit. m.p. 190°C). Mass spectrometric
and 13C nuclear magnetic resonance data of the previously unreported 11-(methoxycarbonylamino)undecanoic acid is provided. 相似文献